Grinding and polishing tool for bifocal lenses.



Patented Oct. 30, 1 917.

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CLILE C. ALLEN, OF CHICAGO, ILLINOIS, ASSIGNOB, MESNE ASSIGNMENTS, TONEW YORK LENS COMPANY, INC., 03 NEW YORK, N. Y., 13 GOBEOB-ATION 01 NEWYQRK.

GRINDING- AND POLISHING TDOL FOE BIFOCAL LENSES.

Application filed February 1a, 1913, Serial as.

To all whom it may concern:

Be it known that I, CLILE G. A EN, a citizen of the United States,residing at Chicago, in the county of Cook. and State of Illinois, haveinvented, certain new and useful Improvements in Grinding and PolishingTools for Bifocal Lenses, of which the following is a specification.

This invention relates to tools for grinding and polishing bifocallenses wherein the lens is provided upon one surface with two areasground to two different radii of curvature.

It is the object-0f the present invention to provide a grinding lapwhich will simultaneously grind a plurality of lenses creating two areasupon one surface of each lens, having different radii of curvature, andalso to provide a means for finishing and polishing said lenses,eliminating any tendency to inequality or zonal difierences.

With the above and other objects in view, this invention consists in theconstruction, combination and arrangement of parts all as hereinaftermore fully described, claimed and illustrated in the accompanyingdrawings, wherein Figure l is a longitudinal section of the polishingtool forming the subject matter of the present invention, cooperatingwith the holder and the lens;

Fig. 2 is a section taken along the line 2-2 of Fig. 1, illustrating thecotiperation between the polishing disks and the lens surface;

Fig. 3 is a face view of the holder of the polishing tool showing theplungers upon which the polishing disks are mounted, in section, andillustrating the adjustment of said plungers.

The lens holder 14, which is oppositely disposed to the grinding face ofthe lap, is cup-formed, to receive the lens blank 15,

which is retained at the hollow end of said holder by means of cement,indicated at 16.

The holder 14 is shown as being mounted in the head stock of a lathe,while the grinding or polishing laps are mounted in the tail stock, asillustrated in Fig. 1 but it will be understood that it is unnecessaryto use such a construction for imparting the necessary rotation to theelements, as any suitable Specification of Letters Patent.

"ice,

Patented Oct. 30, 191

823. Renewed Earch 29, 1917. Serial No. 158,436.

means could be provided'for rotating the elements about the same axis.

The polishing or grinding tool comprises a cylinder 18, closed at oneend by the block 19, which is inserted in said cylinder by any suitableprocess and which carries means for supporting said holder, such as thetapered shank 20. The opposite end of the cylinder 18 is provided with ablock 21, which is inserted therein and which is provided with aplurality f passages22 adjacent to the periphery thereof and with acentral passage 23, said passages being circular inv cross section andarranged upon parallel axes. Over the terminal. of each outer passage 22is pivotally mounted a plate 24, through the medium of the screws 25,said plates adapted to swing about said screws as their piaotal pointsover the outer terminals of therpassages 22. Each plate is provided atits outer terminal with a slot 26, through which a fastening device suchas a screw 27 is inserted and pierces the face of the block 21. By meansof the screws 27 coiiperating with the slots'26, the plates are retainedin any of their various adjusted positions. Registering with thepassages 22 are openings piercing the plates 24, through which plungers28 extend. These plungers 28 extend into the passages 22 and areprovided adjacent to the plates 24 and within said passages with thetransverse pins 29. Springs 30 are interposed between the pins 29 andthe inner face of the block 19 and tend to force the plungers 28 in anoutward direction. It will readily be seen that as the plates 24 areadjusted, the plungers 28 wild assume various adjusted positions. Aplate 31 is pivotally mounted upon a screw 32 adjacent to the centralpassage 23, and; is also provided with a slot 33, pierced by a screw 34,which enters the outer face of the block 21. This plate is, therefore,adjustable in a manner similar to the plates 24 and is also providedwith an openingregistering with the passage 23, through which thecentral plunger 35 passes; This central plunger 35 is also providedwiththe ,pin 36, against which a spring 37 bearsg zithe oppositeterminal of said spring bearing against the inner face of the block 19.

The outer terminals of the plungers 28 and the plunger are provided withthe balls 38, by means of which the polishing or finishing disks 39 aremounted upon said plunger-s.

The grinding or polishing disk 39 carried by the central plunger 35contacts with the inner area of the lens blank 15, while the outerpolishing disks 39 carried by the plungers 28 bear against andcoiiperate with the outer area. It will be seen byreference to Fig. 2that the polishing disks 39 and the lens 15 rotate in the samedirection, and that the outer polishing disk adjacent to the outerportion of the lens 15, rotates with the lens, while the inner portionthereof adjacent to the central area of the lens rotates againstpolishing disk 39 and the outer polishing disks 39 are always concentricat each and every point of the rotation of the lens. Consequently,-theline of demarcation between the two surfaces of the lens is produced.The bearing faces of the polishing disks are provided with the samecurvature as the lens surfaces desired. By the provision of the plates24 and 31, the various plungers and consequently the polishing orgrinding disks may be adjusted to any suitable correlation.

From the foregoing, it will be understood that two bifocal lenses may besimultaneously ground and polished, at the same time eliminating zonaldifferences and creating. a definite and fixed line of demarcationbetween the focal areas of each lens without creating a shoulder orprojection. After the' lenses have been ground and polished, the lensblank is then cut, producing the lenses therefrom. I Y By thearrangement of-the polishing disks 39 with the central disk out ofalinement with the outer disks, the center disk rotates with the lensblank 15 to polish the center of the inner focalarea as well as theperiphcry of the inner focal area. By the provision of two polishers ofvarious sizes, arranged to coiiperate with the central focal area ofthe-lens .blank 15, the center of the focal area operated upon will begiven the proper grinding action by one of. the disks, while the portionof the focal area adjacent to the periphery thereof will also be giventhe proper.

grinding action, which grinding action, however, will be difierent thanthe grinding action of the center of thefocal area, due to ranges thedifierence in size of the disks. in other 3 words, one disk, asillustrated, may be used to operate upon the central focal zone of thelens blank 15, or any number of disks maybe used. It will further beunderstood thatany number of disks may be used to operate upon the outerfocal area of the lens blank 15.

lhe polishing of a lens is in practice nothing but refined grinding, andhence, to use the tool illustrated for the purpose of grinding the lensthe polishing elements or disks 39 are removed from the plungers 35, andgrinding disks of suitable texture and formation are substitutedtherefor. I After these grinding disks have created or formed the properfocal areas of the lens blank 15, they are removed from the plungers 35and the polishing disks 39 replaced thereon to opcrate in the mannerheretofore described.

What is claimed is:

1. The combination of a holder; plates secured to said holder andadapted to be adjusted independently of each other on said holder, therebeing a perforation in each plate and a plunger slidably mounted in andsnugly fitting each of said perforations.

2. The combination of a holder; plates pivoted to said holder, therebeing a perforation in each of the plates; means locking the platesagainst pivotal movement of said holder; and a plunger slidably mountedin and snugly fitting each of said perforations.

3. The combination of a holder; plates pivoted to said holder, therebeing a perforation in each of the plates; screws threaded in saidholder and engaging said plates locking the latter in difierentpositions of their pivotal movement; and a plunger slidably mounted inand snugly fitting each of said perforations.

4. The combination of a holder; plates pivoted to said holder, therebeing a perforation and a slot in each of said plates; a screw passingthrough each of said slots, said screws locking said plates indifi'erent positions of their pivotal movement; and plungers slidablymounted in and fitting said perforations.

5. The combination of a holder; plates pivoted to said holder, therebeing a perforat1on and a slot in each of said plates; a screw passmgthrough each of said slots, said screws locking said plates in differentpositions of their pivotal movement; plungers slidably mounted in andfitting said perforations; and a compression spring on each of saidplungers, each of said sprmgs havmg one of its ends slidably engagingsaid holder.

6. The combination of a holder; plates pivoted to said holder, therebeing a perforation in each of the plates; means locking the platesagainst pivotal movement on said holder; and a plunger slidably mountedin and snugly fitting each of said perforations two subscribingwitnesses, on this 14th day and extending into said holder; and a comofFebruary, A. D. 1913. presslon spring on each plunger in said holderwith 0ne end of the sprmg slidably CLILE C. ALLEN. 5 engaging a portionof the holder. Witnesses:

In testimony whereof I lhave signed my CHAS. S. WILSON, name to thisspecification, in the presence of DWIGHT B. CHEEVER.

copies of this patent may be obtained tor five cents each, by addressingthe "Commissioner d Patcntl,

. Washington, D. 0.

